Multiple misfire issue
Good morning everyone, I used to work mechanics years ago although not doing it for a while has gotten my diagnostic skills a little rough around the edges and would really appreciate some help!
I have a 2001 IS300 with 166K miles on it. I am receiving multiple misfire codes (P0300, P0301, P0302, P0304) with an intermittent misfire from cylinders 1, 2, and 4. It seems to misfire more at idle and when I apply a decent amount of throttle (tends to do it more after the engine is warm). I have pulled the plugs from cylinders 1 and 2 and they are sitting at the correct gap spec and don't look fouled at all. I pulled the intake off to look at the coils and it looks like each of the three coils handle one of the misfiring cylinders. I replaced the coil that direct feeds to cylinder 2 last night and today it seems no different in reducing the level of misfire.
I sprayed down the plug wires looking for shorts in the insulation and that all looked good. I am looking for recommendations on where to go next. I am going back and forth between throwing new plug wires in or replacing the corresponding fuel injectors. I listened to the injectors with a long screwdriver and they all seem to be ticking about the same sound.